1. Field of the Invention
The present invention relates to a magnetic sheet, a method of manufacturing the same and an antenna including the magnetic sheet, and more particularly, to a magnetic sheet capable in which permeability can be adjusted using a different material layer, a method of manufacturing the same, and an antenna including the magnetic sheet.
2. Discussion of Related Art
A magnetic material is commonly used for shielding various types of electromagnetic waves or suppressing electromagnetic interference (EMI) in a wire, and also has a wide range of applications due to its various types and characteristics depending on how the constituent components thereof are synthesized. In recent years, magnetic materials have been used for RF components, such as antennas, electron microscopy cores (EMCs), power inductors, and broadband transformers.
Magnetic materials may be manufactured in the form of a thin sheet. A magnetic sheet may be manufactured in various methods, and one of the methods is achieved as follows. First, a powder is prepared using various methods, such as a solid-phase method and a wet method. Thereafter, a slurry is manufactured by mixing the powder with a binder, plasticizer, dispersant, etc. The mixed slurry is coated into a thin sheet using a doctor blade casting device, and dried. The dried sheet is generally referred to as a green sheet. Thereafter, the green sheet may be subjected to a calcination process. The calcination process may be performed on a plurality of green sheets stacked on top of each other, or a single sheet.
A magnetic material or a magnetic sheet manufactured as described above has a permeability characteristic and thus can be used for RF components. In general, a permeability value of a magnetic material depends on constituent components and a manufacturing process of the magnetic material, and thus in order to change a permeability, methods of varying constituent components of the material, or adjusting the temperature of various thermal treatments in the manufacturing process have been used. However, there is a desperate need to develop technology other than the above-described methods for easily adjusting the permeability.
In addition, the conventional technology fails to allow a different permeability value to be represented at a certain region of a single magnetic sheet. However, in some cases, various RF components each having a different function need to mounted on a single magnetic sheet, or antennas each operating at a different frequency band are mounted on a single magnetic sheet. Therefore, to apply a different permeability value at each component, there is a need for technology for adjusting a permeability value of only a certain portion of a magnetic sheet.